Forest officials recovered the bodies floating near Andharmanik, nine days after an tanker carrying furnace oil sank in the river. The Wildlife Management and Nature Preservation Division had been working to find the extent of the damage, official Md Jahidul Kabir told bdnews24.com on Sunday. A team headed by Jahangirnagar University Zoology Professor Monirul H Khan went to the forest at Dec 18. The dead otters, he said, were covered in furnace oil. They had died two to three days before their bodies were discovered. The otters are mentioned as 'near threatened' in the International Union for Conservation of Nature's red list. Their populations are now limited to the Sundarbans, but they were once widely seen living in rivers of the country's south and western regions. Autopsies performed on their remains by veterinary surgeon Syed Hossain revealed that they died after drinking oil-polluted water. "The two adult otters were hunting for fish in waters polluted with furnace oil. The surgeon said they died after having fish and water polluted with oil." Around 350,000 litres of furnace spread into the world's largest mangrove forest after the tanker vessel sank in the Shela River on Dec 9. Three teams from the Wildlife Management and Nature Preservation Division have been working to find the damage to wildlife. Wildlife preservation official Jahidul Kabir said the teams were yet to spot Royal Bengal Tigers, deers, wild boars or migrants birds covered in oil. "Tigers and deers drink from water bodies inside the Sundarbans. Foreign and local organisations are already working to find the long-term effect of the oil spill on the wildlife population here."